What’s a sas port, What’s a sas address, What’s a sas port? what’s a sas address – Adaptec 48300 User Manual
Page 83
Introduction to SAS
●
83
What’s a SAS Port?
Note:
Because the physical link between SAS devices is from phy to phy,
rather than port to port, a “port” is more of a virtual concept, different
from what is normally considered a port on other types of HostRAID
controllers and storage devices.
A port is one or more phys. A narrow port contains one phy. A wide port
typically contains four phys.
Each port has its own unique SAS address (see
), and all the phys
in a port share that same SAS address.
SAS card port options vary. A SAS card with four phys could be
configured with one wide port, with two wide ports that comprise two
phys, or with four narrow ports each containing one phy. (A wide port
with four phys is referred to as a 4-wide or 4x port.)
What’s a SAS Address?
Each SAS port is identified with a unique SAS address, which is shared
by all phys on that port.
For example, a SAS disk drive might have two narrow ports. Each port
has one unique SAS address. The single phy in each port uses its port’s
SAS address.
In another example, a SAS device might have one 4-wide port. That
port has one SAS address, which is shared by all four phys in the port.
Unlike SCSI devices and SCSI IDs, SAS devices self-configure their SAS
addresses. User intervention is not required to set SAS addresses, and
SAS addresses cannot be modified.